Rotary element and rotary displacement device comprised thereof

ABSTRACT

This disclosure describes new construction for rotary elements that find use in rotary displacement devices, e.g., positive displacement pumps and meters. The proposed construction may incorporate fibers, e.g., carbon fibers, disposed in a resin matrix. This construction can reduce the need to perform secondary processes that are necessary to utilize many rotary elements of conventional design. Moreover, examples of the rotary elements can improve operation of the displacement devices, e.g., by reducing resonance and allowing the displacement device to operate at increased speed.

BACKGROUND

The subject matter disclosed herein relates to rotary displacement devices including pumps and meters that utilize multi-lobed rotating elements.

Rotary-style displacement devices are compatible with a wide range of fluids (e.g., liquids and gases). These devices may include a housing that forms a chamber with an inlet and an outlet. Inside of the chamber, the devices often have a pair of elements that can rotate in opposite directions during operation. The elements mesh with one another to transport, or displace, a known quantity of fluid from the inlet to the outlet. When the device operates as a pump, the elements are actively rotated to facilitate movement of the fluid from the inlet to the outlet of the chamber. On the other hand, when the device operates as a meter, fluid flow acts on the elements. The force of the fluid causes the elements to rotate, which in turn can generate an output (e.g., am electrical signal) that reflects one or more characteristics of the fluid flow.

Performance of these rotary-style displacement devices relies heavily on the construction of the rotating elements. Dimensions for the parts are, for example, held to very tight tolerances to ensure proper fit, mesh, and engagement during rotation. As a competing interest, however, cost considerations lend manufacture of the rotating elements to materials (e.g., iron) and techniques (e.g., casting) that do not necessarily meet the standards for efficient operation of the displacement device. The result is often the need for extensive secondary processing (e.g., machining) of the rotating elements to establish proper fit up, clearances, balance, and mating at the assembly stages.

BRIEF DESCRIPTION OF THE INVENTION

This disclosure describes new construction for rotary elements that find use as rotors and impellers in rotary displacement devices, e.g., positive displacement pumps and meters. Broadly, exemplary construction of the rotary elements utilizes carbon fibers and a resin to form a stiff, light-weight structure. This structure can withstand operating conditions (e.g., pressure, temperature, etc.) of various working fluids (e.g., gas and liquids). Examples of the structure arrange the carbon fibers in a single direction, e.g., along the axis of rotation of the rotary elements. This arrangement of the carbon fibers lends itself to pultrusion processes, which can scale production of the rotary elements to reduce manufacturing costs as compared to conventional impeller designs. The structure also requires little secondary machining during fit-up and assembly, thereby reducing labor and assembly costs. Moreover, the favorable features of the rotary elements set forth below can improve operation of the rotary displacement devices, e.g., by reducing resonance and allowing the rotary displacement device to operate at increased speed.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference is now made briefly to the accompanying Appendix, in which:

FIG. 1 depicts a perspective, exploded view that shows an embodiment of a rotary assembly that includes an example of rotary elements in position on a rotary displacement device;

FIG. 2 depicts a detail, cross-section view of FIG. 1 to illustrate one exemplary construction of the rotary elements;

FIG. 3 depicts a perspective view of a rotary assembly that includes rotary elements that have a first configuration;

FIG. 4 depicts a perspective view of a rotary assembly that includes rotary elements that have a second configuration; and

FIG. 5 depicts a schematic diagram of a system that can execute a pultrusion process to manufacture rotating elements, e.g., the rotating elements of FIGS. 1, 2, 3, 4.

Where applicable like reference characters designate identical or corresponding components and units throughout the several views, which are not to scale unless otherwise indicated.

DETAILED DESCRIPTION

FIG. 1 depicts a schematic diagram of an exemplary embodiment of a rotating assembly 100. The rotating assembly 100 includes one or more rotating elements (e.g., a first rotating element 102 and a second rotating element 104). Examples of the rotating elements 102, 104 have a body 106 with a rotary axis 108. During operation, the body 106 rotates about the rotary axis 108, as generally identified by an arrow marked with the numeral 110. The body 106 can have one or more radial sections (e.g., a first radial section 112 and a second radial section 114), which extend radially away from the rotary axis 108. As described more below, the radial sections 112, 114 can have an outer profile with features that form, in one example, generally curvilinear ends and grooves and/or flutes in the body 106 that extend longitudinally along the rotary axis 108.

The rotating assembly 100 is part of a rotary displacement device 116 that includes devices (e.g., pumps and meters) that accommodate a working fluid (e.g., gas and liquid). The rotary displacement device 116 includes a housing 118 and a cover 120. The housing 118 has a peripheral wall 122 that forms an inner volume 124. When the displacement device 116 is assembled, the housing 118 and the cover 120 couple together to enclose the rotating elements 102, 104 in the inner volume 124. This configuration can seal the inner volume 124 to prevent leaks of the working fluid therefrom. As shown in FIG. 1, one or more openings (e.g., a first opening 126 and a second opening 128) penetrate through the peripheral wall 122. The openings 126, 128 allow ingress and egress into the inner volume 124 from outside of the housing 118. In one example, the openings 126, 128 include an inlet and an outlet (or discharge) that allow fluids (e.g., gas and liquids) to flow into the inner volume 124 (e.g., via the inlet) and to flow out of the inner volume 124 (e.g., via the outlet).

Examples of the rotary displacement device 116 facilitate movement of fluid and/or measure movement of fluid that flows in the inner volume 124, as desired. In one implementation, for example, the rotary displacement device 116 can operate as a pump and/or blower to draw fluid into the inner volume 124, via the inlet, and expel fluid from the inner volume 124, via the outlet. In another implementation, the rotary displacement device 116 can operate as a meter and/or measurement device, which monitors flow characteristics (e.g., flow rate) of fluid that flows from the inlet to the outlet.

The rotating elements 102, 104 include rotors and impellers that rotate within the inner volume 124. Although not shown in the example of FIG. 1, the rotary elements 102, 104 may secure to a shaft that aligns with the rotary axis 108. The shaft may secure to the housing 118 and/or the cover 120, e.g., using bearings that allow the shaft to rotate relative to the cover 120 and the peripheral wall 122.

Construction of the body 106 may incorporate materials that improve characteristics of the rotating elements 102, 104. As set forth more below, exemplary materials may include carbon fibers and/or other plastics, polymers, and composites that afford the rotating elements 102, 104 with characteristics that are superior to metals (e.g., cast iron and aluminum) found in many conventional designs. For example, carbon fibers can reduce the weight of the rotating elements 102, 104 by 15% or more, e.g., with respect to steel. Carbon fibers also increase the strength and stiffness of the rotating elements 102, 104. These improvements can raise the modal frequency of the rotating elements 102, 104 to avoid resonance and other problems that often limit operating speeds for pumps and meters (e.g., rotary displacement device 106).

FIG. 2 illustrates a schematic diagram of a cross-section of the body 106 to illustrate one exemplary construction of the rotating elements 102, 104 (FIG. 1). As shown in FIG. 2, this construction utilizes a composition 130 that comprises a composite material with one or more components (e.g., a matrix component 132 and a fiber component 134). The fiber component 134 can comprise a plurality of fibers and/or elongated elements that extend through the matrix component 132. The matrix component 132 can comprise a resin that binds the fibers of fiber component 134.

Broadly, examples of the components 132, 134 are found in carbon-fiber reinforced polymers, carbon-fiber reinforced thermoplastics, and similar materials that provide excellent physical (e.g., light weight) and mechanical properties (e.g., high strength and stiffness). In one example, the composition 130 is generally homogenous throughout the body 120. This homogeneity affords the rotating elements 102, 104 with uniform properties throughout the body 106 and/or throughout the constituent components (e.g., the first radial section 114 and the second radial section 116).

Properties of carbon fibers and like composites can also reduce costs of construction and manufacture. Examples of the composition 130 are amenable to manufacturing processes (e.g., extrusion, pultrusion, molding, etc.) that benefit from economies of scale and quantity of production. These manufacturing processes also afford the rotating elements 102, 104 with exterior surfaces and profiles that require limited, to no, secondary processes to establish proper fit up during assembly. This feature provides substantial savings on labor costs and assembly time because extensive re-work of the rotating elements 102, 104 to meet tight tolerance specification is not necessary as compared to rotors and impellers found of conventional (e.g., metal) construction.

Examples of the resin of the matrix component 132 include various polymers, e.g., epoxy, polyester, vinyl ester, and/or nylon. Selection of the resin may depend on one or more operating characteristics of the rotary displacement device 116 (FIG. 1). These operating characteristics include fluid temperature and fluid pressure. For example, devices that operate at high temperatures may require resins that can withstand prolonged operation and exposure in those environments. To this end, exemplary resins can exhibit properties that withstand operating temperatures (e.g., fluid temperatures in the rotary displacement device 116) of at least about 350° F. or more.

As mentioned above, fibers in the fiber component 134 can include carbon fibers, although the present disclosure contemplates other fibers that have different material compositions. The material composition can determine the physical and mechanical properties of the rotating elements 102, 104. Use of carbon fibers (and compositions and derivations thereof), for example, can reduce the weight, increase the stiffness, and improve uniformity of the rotating elements 102, 104 as compared to elements that use metals. In one example, the fibers can vary in stiffness (also “modulus”), with one example of the fiber component 134 utilizing carbon fibers of standard and/or intermediate modulus. This disclosure contemplates other constructions that may utilize low modulus and high modulus fibers, as well as combinations of fibers having relatively different modulus (e.g., intermediate and high modulus) within the fiber component 134.

The properties of the rotating elements 102, 104 can also benefit from the fibrous structure of the fiber component 134. This fibrous structure can utilize various arrangements and patterns of fibers in the body 106. These patterns can improve strength and stiffness, while also promoting the homogeneity discussed above. In one construction, a majority of the fibers in the composition 130 form a uni-directional pattern. The uni-directional pattern arranges most, if not all, of the fibers in a single direction. This direction can, in one example, place the fibers in axial alignment along the rotary axis 108 (FIG. 1).

FIGS. 3 and 4 depict exemplary construction of a rotating assembly 200 (FIG. 3) and a rotating assembly 300 (FIG. 4). In FIG. 3, the rotating elements 202, 204 include one or more lobed impellers (e.g., a first lobed impeller 236 and a second lobed impeller 238). The lobed impellers 236, 238 have an outer profile 240 that forms one or more lobes (e.g., a first lobe 242 and a second lobe 244) offset by an angle 246. The lobes 242, 244 exemplify the curvilinear ends and grooved and/or fluted features for the rotating elements mentioned above and contemplated herein. In the example of FIG. 3, the offset angle 246 is about 180°. As best shown in FIG. 4, the lobed impellers 336, 338 includes a third lobe 348 in addition to the first lobe 342 and the second lobe 344. Impellers of the type shown in FIG. 4 are often called tri-lobe impellers, deploying the lobes 342, 344, 348 at an offset angle 346 of about 120°.

During operation, the lobed impellers (e.g., the lobed impellers 236, 238 and the lobed impellers 336, 338, 348) rotate around the rotary axis (e.g., rotary axis 208 and rotary axis 308). The exterior profiles 240, 340 mesh together to promote fluid movement (e.g., as a pump) and/or to measure fluid (e.g., as a meter). In one example, in bi-lobed impellers, movement of the lobed impellers 236, 238 traps and discharges fluid at least four time during each revolution. For tri-lobed impellers, the movement of the lobed impellers 336, 338, 348 traps and discharges fluid at least 5 times or more during each revolution.

FIG. 5 depicts a schematic diagram of an exemplary system 400 that can execute processes to manufacture the rotating elements, as set forth herein. Moving from left to right in the diagram, the system 400 includes a fiber feed component 402 with one or more fiber rolls (e.g., a first fiber roll 404, a second fiber roll 406, and a third fiber roll 408). The fiber rolls 404, 406, 408 hold fibers 410 (also “fiber tows 410”). The system 400 also includes one or more rollers (e.g., a first roller 412 and a second roller 414) to maintain tension in the fibers 410 as the fibers 410 transit the system 400, as discussed more below. The system 400 also includes a matrix bath component 416 that holds a matrix 418 therein, a die component 420, and a pull mechanism 422. In one example, the system 400 also includes a cutting component 424.

Examples of the system 400 can execute a pultrusion process. Broadly, pultrusion is a continuous molding process which “pulls” fibers 410 into the matrix 418 and through the die component 420. As contemplated herein, examples of the fibers 410 can include carbon fiber and/or glass, alone and/or together. The system 400 draws the fibers 410 from the fiber feed component 402 through the matrix 418. This feature ensures that the matrix 418 thoroughly impregnates, or wets, the fibers 410 in the matrix bath component 416. The die component 420 may include a die to form the wet-out fiber from the matrix bath component 416. Examples of the die can include an aperture and/or opening that has the desired geometric shape and exterior profile for the rotating element (e.g., exterior profiles 240, 340 that generate the bi-lobe and tri-lobe rotating elements of FIGS. 3 and 4 above). The die component 420 may incorporate a heater that heats the die. In one implementation, the temperature of the die component 420 initiates curing of the matrix 418, e.g., by controlling the elevated temperature of the die. Curing solidifies the matrix 418 about the fibers 410 in the shape of the opening in the die as the system 400 continuously pulls the combination of the fibers 410 and matrix 418 through the die.

In the example of FIG. 7, fibers 410 may include standard modulus or intermediate modulus carbon fiber that are pulled through the matrix bath component 416. This process impregnates the carbon fibers with, in one example, thermoset resin (e.g., polyester resin). Within the die component 420, the wetted carbon fibers may encounter one or more forming guides, which align the fibers to deliver the designed mechanical properties before the fiber/resin composition enters a die made of steel. The die may form the fiber/resin composition into bi-lobe or tri-lobe shapes. The forming guides may also strip off excess resin from the fiber/resin composition, reducing the hydraulic pressure caused by the materials entering the die. In one implementation, this process can result in a fiber pattern in which the fibers are aligned uni-directionally in the pre-formed shape. This composition is pulled through the heated die, where the fiber/resin composition can develop its final cross sectional bi-lobe or tri-lobe shape. The heat in the die initiates an exothermic reaction within the formulated resin to complete the cure. The finished bi-lobe or tri-lobe profile will be continuously pulled from the die by a pulling device. In one example, the finished profile will be cut to a desire length, e.g., by the cutting component 424. Pultrusion process requires little operator input besides maintaining material supply and it is cost effective in terms of waste and producing part with consistent quality at higher throughput. Typically pultruded parts have no voids/porosity and have uniform mechanical properties across the length and width. The process provides maximum flexibility in the design of uniform cross-sectional profiles.

As used herein, an element or function recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural said elements or functions, unless such exclusion is explicitly recited. Furthermore, references to “one embodiment” of the claimed invention should not be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims. 

What is claimed is:
 1. An impeller, comprising a body having a plurality of lobes with a curvilinear end and disposed about a rotary axis, the body comprising a composition of a resin and fibers disposed in the resin, wherein the fibers extend axially along the rotary axis.
 2. The impeller of claim 1, wherein the plurality of lobes comprises a first lobe and a second lobe offset from the first lobe about the rotary axis by about 180°.
 3. The impeller of claim 2, wherein the plurality of lobes comprises a third lobe offset from the first lobe and the second lobe about the rotary axis by about 120°.
 4. The impeller of claim 1, wherein the fibers comprise carbon fibers.
 5. The impeller of claim 4, wherein the resin comprises an epoxy.
 6. The impeller of claim 1, wherein the resin is compatible with working fluids that have an operating temperature of about 350° F. or greater.
 7. The impeller of claim 1, wherein the composition is homogeonous throughout the body.
 8. An impeller, comprising: a body having a rotary axis, a first lobed section with a curvilinear end, and a groove extending longitudinally along the rotary axis, the body comprising a composition having a matrix component and a fiber component with fibers disposed in the matrix component, wherein the fibers form a uni-directional pattern throughout the body, and wherein the uni-directional pattern aligns the fibers longitudinally in the body along the rotary axis.
 9. The impeller of claim 8, wherein the fibers comprise carbon fiber and the matrix component comprises a polymer.
 10. The impeller of claim 9, wherein the polymer has thermal properties that are compatible with a working fluid having an operating temperature of about 350° F. or greater.
 11. The impeller of claim 8, wherein the body has a second lobed section, and wherein the fibers in the second lobed section form the uni-directional pattern.
 12. The impeller of claim 11, wherein the second lobed section is offset from the first lobed section about the rotary axis by about 180°.
 13. The impeller of claim 11, wherein the second lobed section is offset from the first lobed section about the rotary axis by about 120°.
 14. A rotary displacement device, comprising: a first impeller having a body with a rotary axis, the body comprising a first composition with a fiber component having a plurality of fibers that form a uni-directional pattern that aligns the fibers longitudinally in the body along the rotary axis.
 15. The rotary displacement device of claim 14, wherein the body comprises an outer profile that forms a first lobe and a second lobe disposed about the rotary axis, wherein the first lobe and the second lobe have a curvilinear end, wherein the body also forms one or more grooves disposed between the first lobe and the second lobe, and wherein the grooves extend longitudinally along the rotary axis.
 16. The rotary displacement device of claim 14, wherein the first composition is homogeonous throughout the body.
 17. The rotary displacement of claim 16, further comprising a second impeller having a second composition that is the same as the first impeller.
 18. The rotary displacement device of claim 17, wherein the plurality of fibers in the first composition and the second composition are disposed in a resin comprising a polymer.
 19. The rotary displacement device of claim 18, wherein the plurality of fibers comprise carbon fibers and the resin comprises an epoxy that is compatible with fluid temperature of at least about 350° F. or more.
 20. The rotary displacement device of claim 14, wherein the first impeller is configured to rotate under force of a working fluid. 